# Magnetically tunable multi-band near-field radiative heat transfer between two graphene sheets

## TL;DR

This paper demonstrates that applying an external magnetic field to two graphene sheets enables tunable multi-band near-field radiative heat transfer, with potential applications in thermal information transfer and device control.

## Contribution

It reveals a magnetically tunable multi-band NFRHT system in graphene sheets, showing how magnetic fields induce multiple spectral bands and resonant peaks, a novel control mechanism.

## Key findings

- Multi-band spectra are achieved under magnetic fields.
- Dual-band spectra can be realized at modest magnetic fields.
- Additional low-frequency band appears at high magnetic fields.

## Abstract

Near-field radiative heat transfer (NFRHT) is strongly related with many applications such as near-field imaging, thermos-photovoltaics and thermal circuit devices. The active control of NFRHT is of great interest since it provides a degree of tunability by external means. In this work, a magnetically tunable multi-band NFRHT is revealed in a system of two suspended graphene sheets at room temperature. It is found that the single-band spectra for B=0 split into multi-band spectra under an external magnetic field. Dual-band spectra can be realized for a modest magnetic field (e.g., B=4 T). One band is determined by intra-band transitions in the classical regime, which undergoes a blue shift as the chemical potential increases. Meanwhile, the other band is contributed by inter-Landau-level transitions in the quantum regime, which is robust against the change of chemical potentials. For a strong magnetic field (e.g., B=15 T), there is an additional band with the resonant peak appearing at near-zero frequency (microwave regime), stemming from the magneto-plasmon zero modes. The great enhancement of NFRHT at such low frequency has not been found in any previous systems yet. This work may pave a way for multi-band thermal information transfer based on atomically thin graphene sheets.